JPS6241253A - Flame-retardant resin composition - Google Patents

Abstract

PURPOSE:To provide a flame-retardant resin compsn. which has excellent impact resistance, thermal stability, etc., has such moldability that it can be put as a molding material to practical use, and is suitable for use in the production of electrical components, by mixing an ABS resin with a polyvinyl chloride resin having a specified composition. CONSTITUTION:70-90pts.wt. alkyl methacrylate (A) which gives a homopolymer having a second-order transition point of -10 deg.C or below (e.g., 2-ethylhexyl acrylate), and 30-1pt.wt. polyfunctional monomer (B) (e.g., ethylene glycol diacrylate or diallyl fumarate) are copolymerized. 99-70pts.wt. vinyl chloride is grafted onto 1-30pts.wt. copolymer to prepare a PVC resin. 30-80wt% PVC resin is mixed with 70-20wt% ABS resin to obtain the desired flame- retardant resin compsn.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a flame-retardant resin composition that is composed of an Ass resin and a vinyl chloride resin and has excellent processability, impact resistance, and thermal stability. do.

[Conventional technology]

Conventionally, thermoplastic resins used in fields such as electrical equipment parts, automobile parts, and building materials include high-impact polystyrene resin and acrylonitrile, which have excellent impact resistance and q-rigidity, and extremely good moldability. Rubber-containing high-impact polystyrene resins such as polyethylene-styrene copolymers (hereinafter referred to as ABS resins) have been widely used.

However, regarding the resins used in this field in recent years,
Increasingly high degree of flame retardancy is required, and there is a desire to develop even more advanced flame retardant resin to replace the polystyrene resin which is flammable to some extent. Things are being proposed.

For example, there are flame-retardant resin compositions containing a low molecular weight 111m agent represented by phosphorus-containing compounds such as halogenated esters, aromatic halogen-containing compounds, phosphoric esters, and halogenated phosphoric esters.

However, these flame retardants are chemically unstable low-molecular compounds and also impart a high degree of flame retardancy to resins (
Since this must be added in a considerable amount, it causes a significant decrease in the mechanical strength, especially the impact strength, of the resin, and also impedes moldability, such as causing coloration due to thermal decomposition during molding. In addition, they often impair the commercial value of the product by significantly deteriorating weather resistance, and furthermore, flame retardants are generally expensive, so they have the disadvantage of significantly increasing the cost of the product. However, it is difficult to obtain resins that have a high degree of flame retardancy and can be put to practical use.

On the other hand, focusing on the fact that it is easy to obtain a high degree of balance between flame retardancy and impact strength, recently, flame retardant resins obtained by mixing halogen-containing compounds such as polyvinyl chloride resins and chlorinated polyethylene with other resins have been developed. Many types of resin compositions have been proposed.

For example, a flame-retardant resin composition consisting of a polyvinyl chloride resin and an ABS resin is known (Japanese Patent Publication No. 48-528).
.

Derived from the properties of polyvinyl chloride resin, this resin composition certainly has excellent mechanical strength such as impact strength and rigidity, and a resin with a high degree of flame retardancy can be obtained, but polyvinyl chloride resin is chemically The resin composition has poor thermal stability because it is physically unstable and prone to thermal decomposition, and combined with the poor fluidity of polyvinyl chloride resin, the molding processability is significantly reduced. I have.

On the other hand, it is obvious that heat stabilizers such as lead-based compounds and tin-based compounds are added to improve molding processability by increasing the thermal stability of polyvinyl chloride. There is a natural limit to the amount used because of its impact on important fluidity and physical properties, and from the cost perspective.

It is also known to improve the moldability of polyvinyl chloride by reducing the content of molecules with asymmetric structures (branches, double bonds, etc.) in the polymer through ionic polymerization, etc. However, there are industrial problems in terms of polymerization rate and yield. Furthermore, as a method to improve the moldability of resin, there is a method to increase the thermal stability of the resin by increasing the fluidity of the resin and keeping the molding temperature low. tends to decrease, and sufficient effects cannot be obtained.

On the other hand, a flame-retardant resin composition (US Pat. No. 3,494,982) comprising chlorinated polyethylene and ABS resin is also known. Although this composition has better thermal stability than polyvinyl chloride resin compositions, it has the disadvantage of poor moldability due to poor flowability.

As mentioned above, no conventional flame-retardant resin composition has been found that simultaneously satisfies moldability, 115 m resistance, and weather resistance, which are important commercial values, and can be put to practical use as a molding material.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a flame-retardant resin composition that has moldability that can be practically used as a molding material, which has been difficult to achieve with conventional compositions, and also has excellent impact resistance. It is in.

[Means for solving problems]

As a result of intensive research to achieve the above object, the present inventor found that
The inventors have discovered that a w1 flammable resin composition with excellent processability, impact resistance, and thermal stability can be obtained by combining an ABS resin with a specific vinyl chloride resin, and have thus arrived at the present invention.

That is, the resin composition of the present invention has a secondary dislocation point of 110% when A) 20 to 70% by weight of ABS resin and 8) a homopolymer.
Graft copolymerization of 70 to 99 parts by weight of vinyl chloride to 1 to 30 parts by weight of a copolymer of 70 to 99 parts by weight of alkyl acrylate and/or alkyl methacrylate and 1 to 30 parts by weight of a polyfunctional monomer at a temperature of 70 to 99 parts by weight. P obtained by
It is a flame-retardant resin composition consisting of 30 to 80% by weight of a VC resin.

This will be explained in detail below.

The content of ABS resin in the flame retardant resin composition of the present invention is 20
The content is preferably 69% by weight, but 30 to 65% by weight is particularly preferred. If it is less than 20% by weight, processability will be poor, and if it exceeds 69% by weight, it will be difficult to maintain flame retardancy.

Polybutadiene rubber, which is the polymerization raw material for ABS resin, is
Polybutadiene or 50% by weight or more of butadiene and 50% by weight or less of a monoolefin monomer copolymerizable with it, such as aromatic vinyl compounds such as styrene, alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate: methyl methacrylate , alkyl methacrylate such as ethyl methacrylate and butyl mequaacrylate; a copolymer with vinyl cyanide compounds such as acrylonitrile.

Examples of vinyl cyanide compounds used in ABS resin graft polymerization include acrylonitrile and methacrylates, and examples of aromatic vinyl compounds include styrene, α
- Methyl styrene, chlorostyrene, etc. are typical, and the ratio of use thereof is preferably 10 to 50 parts by weight of the vinyl cyanide compound and 10 to 50 parts by weight of the aromatic vinyl compound to 10 to 50 parts by weight of the above-mentioned butadiene rubber. .

Further, in addition to the vinyl cyanide compound and the aromatic vinyl compound, a small amount of vinyl monomer copolymerizable with these can be used in the graft polymerization.

All of the above polymerizations can be easily carried out by conventionally known methods, such as suspension polymerization and emulsion polymerization, but emulsion polymerization is particularly preferred.

The content of PvC resin in the flame retardant resin composition of the present invention is 3
0 to 80% by weight, particularly preferably 40 to 70% by weight.

If the content of the PvC resin exceeds 80% by weight, it is undesirable because the impact strength and molding processability of the resin composition will decrease.On the other hand, if the content is less than 30% by weight, it will be difficult to achieve the objective of the present invention. No flammability is obtained.

The graft polymerization raw materials used for the PvC resin in the present invention are a copolymer of alkyl acrylate and/or alkyl methacrylate and a polyfunctional monomer (hereinafter referred to as acrylic copolymer) and vinyl chloride.

Alkyl acrylates and alkyl methacrylates are those whose secondary transition point is 110°C or less when made into a homopolymer, such as ethyl acrylate,
n-propyl acrylate, iso-butyl acrylate, n-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, and n-octyl methacrylate, n-decyl methacrylate, n - Dodecyl methacrylate, lauryl methacrylate, etc., which contribute to WX impact resistance.

Alkyl acrylate and/or alkyl methacrylate acts as a soft segment, and the amount used is preferably 99 to 70 parts by weight per 100 parts by weight of the total amount of polyfunctional monomer used as other copolymerization raw materials.
If it exceeds 70 parts by weight, no improvement in strength can be expected, and if it is less than 70 parts by weight, impact resistance will decrease, which is not preferable.

Polyfunctional monomers include alkyl acrylates and/or
or monomers that cause crosslinking or the like to alkyl methacrylate, such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1.
Acrylates or methacrylates of mono- or polyalkylene glycols such as 3-butylene glycol dimethacrylate, 1.3-butylene glycol dimethacrylate, 1.4-butylene glycol dimethacrylate, diallyl phthalate, diallyl maleate, diallyl fumarate, diallyl succinate Examples include di- or triallyl compounds such as and didonylbenzene.

The amount of the polyfunctional monomer used is preferably from 1 to 30 parts by weight; if it is less than 1 part by weight, no improvement in strength can be expected, and if it exceeds 30 parts by weight, the impact resistance will decrease, which is not preferred.

The copolymer of alkyl acrylate and/or alkyl methacrylate used in the present invention and monomers is prepared by polymerization methods such as emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization using commonly known emulsifiers, dispersants, catalysts, etc. However, it is particularly preferable to employ emulsion polymerization.

The amount of the acrylic copolymer used as the backbone polymer in the graft copolymerization to obtain the PvC resin of the present invention is 1 part per 100 parts by weight of the total amount of vinyl chloride used as another raw material for the graft copolymerization. ~30 parts by weight is suitable.

If the amount of acrylic copolymer used is less than 1 part by weight, it will be impact resistant!
If the Si property is not sufficient and the amount exceeds 30 parts by weight, the impact resistance will improve, but the strength will decrease, which is not preferable.

The graft copolymerization method of the present invention includes an aqueous suspension polymerization method,
Examples include aqueous emulsion polymerization, solution polymerization, and solutionless polymerization, but aqueous suspension polymerization is preferred. 6. When carrying out aqueous suspension polymerization, the sum of the acrylic copolymer as the backbone polymer and the vinyl chloride monomer and water in a weight ratio of 1:1 to 1:5, preferably 1:1 to 1:3. A method for obtaining a graft copolymerized PVC resin by a general suspension polymerization method is, for example, in a jacketed polymerization reactor, pure water, a suspension stabilizer such as hydroxypromethylcellulose, a radical polymerization initiator, If necessary, a polymerization degree reducing agent is added, and the acrylic copolymer is added thereto and suspended, the air inside the can is then removed, and then vinyl chloride is charged together with other vinyl compounds as required. Thereafter, the inside of the can is heated by a jacket, the acrylic copolymer is dissolved in vinyl chloride, and graft copolymerization is started. Graft copolymerization is an exothermic reaction, and the internal temperature is controlled by a jacket as necessary. After the reaction is completed, unreacted vinyl chloride is removed from the can to obtain a slurry of graft copolymerized PVC resin. The slurry is dehydrated and dried according to a conventional method to obtain a graft copolymerized PvC resin. The charging method to the polymerization reactor is not limited, and among the charged raw materials such as pure water, suspension stabilizer, acrylic copolymer, and vinyl chloride, the acrylic copolymer may be dissolved in vinyl chloride. Another method is to charge the material with water.

In graft copolymerization, other monomers may be present in the coexistence within a range that does not reduce the impact resistance, weather resistance, and flexural modulus.

The resin composition of the present invention may optionally contain various additives such as other flame retardants, ultraviolet absorbers, antioxidants, colorants, lubricants, and heat stabilizers.

The resin composition of the present invention can be used in mixing rolls, co-kneaders,
It can be easily melt-mixed using a kneader such as a Banbury Mixer 2 extruder.

The thus obtained resin composition of the present invention can be widely used in fields such as electrical parts, automobile parts, building materials, office machine parts, etc., which require a high degree of flame retardancy.

The present invention will be explained in detail below using Examples and Reference Examples.

In addition, each physical property value in this invention was measured by the following method.

(1) Measurement of moldability (fluidity) Take an extrusion pellet 19 and use a die with an inner diameter of 1 mm and a length of 10 mm, and use a pressure of 150 to 9/cm' and a temperature of 200.
The flow rate was measured using a Koka type flow tester under the conditions of ℃.

(2) Measurement of moldability (thermal stability) (2) -10R thermal stability test (static thermal stability) Time until decomposition starts (minutes) according to JIS-6723 method
was measured. However, the temperature was 200°C.

(2)-2 Dynamic Thermal Stability Extrusion pellet 329 was loaded into a rotor mixer with an internal volume of 30 cc and a Bunch-type plastograph at a temperature of 190°C, and the rotation speed was 50 r, p, and load was 10.0 k (+ conditions). The time (minutes) after the torque decreased and entered a steady state until it started to increase again was measured (7i!).

(3) Measurement of impact strength Izot impact test obtained by molding with a 40Z injection molding machine at injection molding temperatures of 180°, 200°, and 200°C and a molding cycle of 1 minute according to ASTM-256 method. Izot impact strength was measured using the piece. However, a mold with a notch was used.

(4) Flame retardant UL-94 method: Sample thickness 1/8 inch test piece used.

〔Example〕

Examples 1-10. Reference Examples 1 to 11 (1) Production of ABS Resin Polymers (A)-1 to 10 were obtained by emulsion polymerization at 60° C. based on the amounts of raw materials shown in Table 1. The composition of the solid polybutadiene latex used is as follows.

PB-1-・・・Butadiene content 100% (wt%,
Same hereafter) PB-2...Butadiene content 60%, styrene content 40%PB-3...Butadiene content 60%, acrylonitrile content 40% PB-4...Butadiene content 40%, styrene content: 40%, acrylonitrile content: 20% The amounts of each raw material used in Table 1 are parts by weight (the same applies to Tables 2 and below).

(2) Production of PVC resin Based on the amounts of raw materials used shown in Table 2, water-induced suspension polymerization was carried out at 63°C to obtain polymers CB)-1 to CB)-1.

The temperature of the secondary transition point of acrylic resin homopolymer is as follows.

Poly-n-butyl acrylate ---------5
6℃ poly-2-ethylhexyl acrylate...-
---20℃ Methyl acrylate ---o'c methyl methacrylate ------45℃ (
3) Production of the resin composition of the present invention The ABS resin obtained in the above (1) and the PvC resin obtained in the above (2) were roughly mixed in the proportions shown in Tables 3 and 4. Dibutyltin mercaptide as stabilizer2.
5 parts by weight were mixed in a 5β super mixer (manufactured by Yoda Seisakusho) at 90°C for 10 minutes, and then melt-kneaded at 200°C in a 40 mmφ extruder to form a bead.

Next, test pieces for measuring physical properties were prepared using a 4-ounce injection molding machine. In this case, the molding temperature is 1 at the cylinder temperature.
The temperature was 80.200.200°C. Using the pellets and test pieces thus obtained, the various physical property tests described above were conducted.

The evaluation results are shown in Table 3.4 along with reference examples.

As is clear from Table 3.4, the composition of the present invention '
The material is excellent in terms of processability, physical strength, and flame retardancy.

〔Effect of the invention〕

As described in detail above, the present invention provides a flame-retardant resin composition with excellent processability, impact resistance, and thermal stability, and greatly contributes to improving the quality and expanding the use of flame-retardant resins. big.

Claims (1)

[Claims] A) 20 to 70% by weight of ABS resin and B) when made into a homopolymer, the secondary dislocation point is -10
70 to 99 parts by weight of vinyl chloride is graft-copolymerized to 1 to 30 parts by weight of a copolymer of 70 to 99 parts by weight of alkyl acrylate and/or alkyl methacrylate and 1 to 30 parts by weight of a polyfunctional monomer. Obtained P
A flame-retardant resin composition comprising 30 to 80% by weight of a VC resin.